Background Myocardial deformation can be key to clinical decision. 2D feature-tracking of cardiovascular magnetic resonance (CMR-FT) imaging is user-friendly but has poor reproducibility, particularly for radial strain. 3D CMR-FT may improve repeatability by reducing through-plane artefact. The aim of this study was to provide normal ranges for 3D CMR-FT and compare its reproducibility to older generation 2D CMR-FT.
Method 56 asymptomatic, healthy subjects (43.7±12.9 year, 52% male) undertook CMR (1.5 Tesla scanner Magnetom Avanto, Siemens, Erlangen, Germany). 3D FT-CMT was generated using the SSFP HLA, VLA and short axis cine images (Figure 1). A single observer (BL) analysed the CMR studies using 2D and 3D CMR-FT (Circle cvi42® version 5.3) and after 4 weeks, re-analysed blinded scans for intra-observer variability. Inter-observer variability was generated by separate tracking by a second blinded observer (AS) in a randomly generated subset of 15 subjects. Agreement was tested by calculating mean bias and 95% limits of agreement (confidence intervals) from Bland–Altman analyses, coefficient of variation, and inter-class correlation coefficient (ICC).
Results There is modest agreement between all measures of 2D and 3D peak strain analysis (ICC=0.44 to 0.58). Mean global circumferential strain (GCS) on 3D analysis is −16.8±2.5, compared to 2D GCS of −20.2±3.31 and −20.6±3.4 at the base and mid-ventricular level respectively. Mean global longitudinal strain (GLS) is −13.7±2.3 on 3D CMT-FT and −19.3±2.7 on 2D CMR-FT. Global radial strain (GRS) is 45.5±10.9 for 3D, compared to 55.1±14.4 and 48.0±13.4 at the base and mid-ventricular level respectively.
Table 1 displays the inter- and intra-observer variability of each technique. Intra-observer variability was significantly improved by 3D CMT-FT for GCS, whilst inter-observer variability was significantly improved for GCS, GRS and strain rates. No reproducibility differences were identified for GLS.
Discussion Peak strains using 3D FT-CMR is different to 2D normal range values. 3D CMR-FT has superior intra- and inter-observer reproducibility compared with 2D CMR-FT, particularly for GCS and GRS strain, the latter being the principal systolic strain and should improve detection of sub-clinical ventricular dysfunction.
- Cardiac MRI
- 3D feature tracking
- Strain imaging
Statistics from Altmetric.com
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.